In a digital computer system, computer programs provided by a number of vendors typically organize data for processing in a number of diverse formats. Each vendor may use different formats for organizing the data processed by its programs, with the formats being selected to enhance the processing by the particular program. Some programs may also include conversion routines which allow the program to import data from files having selected formats to a format used by the program, and to export data from the format used by the program to another format.
In some data structures for storing data for use in, for example, document processing, the data is segmented according to the structure of the document. For example, a document is divided into a structural hierarchy, comprising for example, chapter, sections, paragraphs, figures, and so forth, and the data defining the document may also be divided into similar hierarchical structures.